This invention relates to the electrochemical hydrogenation of fatty acids, and in particular of vegetable oils.
Fatty acids are hydrogenated to improve their stability against oxidation, and improve their melting characteristics. Most current commercial hydrogenation processes are batch, rather than continuous processes, requiring high temperature and high-pressure reactors or vessels. These high temperature and high pressure processes suffer from a risk of explosion. Moreover because of the elevated temperature at which these processes operate, they result in the production of a higher percentage of trans fatty acids. Trans fatty acids are undesirable because they can increase the cholesterol levels in the blood, increase blood lipoprotein(s), and may be asscociated with the development and acceleration of coronary heart disease.
Another hydrogenation processes is catalytic transfer hydrogenation, for example as disclosed in Smidnovik et al., Smidnovik, A., Stimac, A., and Kobe, J., xe2x80x9cCatalytic transfer hydrogenation of soybean oilxe2x80x9d, JAOCS, 69:405-409 (1992), incorporated herein by reference. Catalytic transfer hydrogenation requires substantial quantities of catalyst, which are consumed in the process, and thus the reaction rate also decreases over time. Still another hydrogenation process is electrocatalytic hydrogenation, for example as disclosed in Yusem, G. and Pintauro, P. N., xe2x80x9cElectrochemical hydrogenation of soybean oilxe2x80x9d, JAOCS, 69, 399-404 (1992), Pintauro, U.S. Pat. No. 5,225,581, xe2x80x9cElectrocatalytic process for hydrogenation of edible and non edible oils and fatty acids, the disclosures of both of which are incorporated herein by reference. Electrocatalytic hydrogenation typically results in the generation of H2 which presents risk of explosion.
The present invention is a low temperature electrochemical hydrogenation process. The process results in substantial hydrogenation of fatty acids, but because it operates at relatively low temperatures, it results in relatively low production of trans fatty acids. Further the process regenerates the electrocatalyst, so that the reaction rate does not deleteriously decline over time.
There are other features and advantages will be in part apparent and in part pointed out hereinafter.